Emerging environmental trends aimed at reducing greenhouse gas emissions, use of fossil carbon derivatives, and solid waste accumulation have created a growing desire to replace petroleum-based polyesters such as poly(ethylene terephthalate) (“PET”) with renewably-sourced materials and modifiers, particularly for applications such as packaging. Current commercial offerings include, for example, poly(trimethylene terephthalate), polylactic acid, polyhydroxyalkanoates, starch, and poly(butylene adipate terephthalate). However, these products suffer from low thermal stability and inadequate mechanical properties for applications such as packaging.
Research aimed at producing polyesters that contain a high weight percentage of biologically derived material (high “green content”) has focused on copolymerization, such as incorporation of biologically derived aliphatic moieties in place of part of the terephthalic acid in polytrimethylene terephthalate polymers [see, e.g., U. Witt et al., Macromolecular Chemistry and Physics, 195, 793-802 (1994)]. However, percent crystallinity, glass transition temperature, and melting temperature all decrease as a result, preventing the use of such materials in applications for which poly(ethylene terephthalate) is used.
Therefore, there remains a need to produce a polyester material that has a high enough glass transition temperature for applications such as packaging and contains a desirably large fraction of biologically derived material. The compositions disclosed herein enable the production of materials having both a green content higher than 40 wt % and acceptably high glass transition temperatures. Articles comprising these compositions are also provided.